Dense Bi 0.487 Na 0.427 K 0.06 Ba 0.026 TiO 3 (BNKBT) and Nb-doped Bi 0.487 Na 0.427 K 0.06 Ba 0.026 Ti 0.98 Nb 0.02 O 3 (Nb-BNKBT) ceramics were prepared by the solid state reaction route. BNKBT is a non-ergodic relaxor and exhibits a piezoelectric response typical for a ferroelectric, whereas Nb-BNKBT is an ergodic relaxor and exhibits an electromechanical response typical for an incipient ferroelectric. The incorporation of 2 mol% of Nb into the BNKBT lattice is accompanied by an enhancement of the room-temperature unipolar field-induced strain from 0.19% to 0.43% at 75 kV/cm. BNKBT shows a depolarisation temperature of ∼90 °C, above which an electrostrictive response is observed, whereas Nb-BNKBT shows an electrostrictive response in the entire temperature range studied. At 40 kV/cm, Nb-BNKBT exhibits a temperature stable electromechanical response in comparison with undoped BNKBT, but it worsens under higher electric fields. These results may motivate further investigations on the impact of minor doping and driving electric fields on the electromechanical response of Bi 0.5 Na 0.5 TiO 3 –Bi 0.5 K 0.5 TiO 3 –BaTiO 3 -based ceramics.
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机译：通过固态反应路线制备了致密Bi 0.487 Na 0.427 K 0.06 Ba 0.026 TiO 3（BNKBT）和Nb掺杂Bi 0.487 Na 0.427 K 0.06 Ba 0.026 Ti 0.98 Nb 0.02 O 3（Nb-BNKBT）陶瓷。 BNKBT是一种非遍历的弛豫器，表现出典型的铁电体压电响应，而Nb-BNKBT是一种遍历的弛豫器，并且表现出对于初期铁电体的机电响应。在BNKBT晶格中掺入2 mol％的Nb伴随着室温单极场诱导的75 kV / cm应变从0.19％增强到0.43％。 BNKBT显示约90°C的去极化温度，在该温度以上观察到电致伸缩响应，而Nb-BNKBT在整个研究温度范围内均显示电致伸缩响应。与未掺杂的BNKBT相比，Nb-BNKBT在40 kV / cm时表现出温度稳定的机电响应，但在较高的电场下会恶化。这些结果可能会促使人们进一步研究较小的掺杂和驱动电场对Bi 0.5 Na 0.5 TiO 3 -Bi 0.5 K 0.5 TiO 3 -BaTiO 3基陶瓷的机电响应的影响。
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